This springtail looks a lot like an insect; in fact, scientists long
thought insects evolved from the group of hexapods it belongs to. But
comparative genomics, using mitochondrial DNA, now shows that life's
family tree has a whole new branch. Nature, it seems, found two different
ways to evolve six legs.

A model
old mouse

Mice can teach us a lot about life. Keep it simple, stay out of trouble
-- and maintain your genome. Researchers who study mouse
models of accelerated aging have learned that cataracts, hearing loss,
and other traits of old age result when the body's ability to repair its
DNA is disrupted.

Squeezing
the glass sponge

Beds of diatomite hold billions of barrels of oil in tiny pores, only millionths
of a meter wide or less. The glassy skeletons of aquatic plants make rock
that's light enough to float on water -- but so fragile and impermeable
it's hard
to get the oil out without wrecking the oilfield.